Shoppers are hesitant to spend crisp bills — unless they’re showing off, according to the Journal of Consumer Research.

“Consumers tend to infer that worn bills are used and contaminated, whereas crisp bills give them a sense of pride in owning bills that can be spent around others,” write authors Fabrizio Di Muro of the University of Winnipeg and Theodore J. Noseworthy of the University of Guelph.

They found in experiments that consumers spent more with worn bills than with crisp bills and were more likely to break a worn larger bill than pay the exact amount in crisp lower denominations. But when consumers thought they were being socially monitored, they tended to spend crisp bills more than worn ones.

“People want to rid themselves of worn bills because they are disgusted by the contamination from others,” the authors write. The authors note that most bills are often replaced not because they are worn but because of “soil content,” which refers to f bacteria found on the bills.

AirPods have become a rare public misstep for Apple. In September, Apple marketing chief Phil Schiller hailed the earbuds as the entree to a wireless future, with seamless connection to an iPhone and a five-hour battery life.

The brokerage industry’s self-regulator has asked employees fired by Wells Fargo & Co. and stripped of their securities registrations to come forward if they have concerns over their treatment, the latest sign of growing scrutiny on the bank.

Ford Motor Co. is going ahead with plans to move small-car production from the U.S. to Mexico despite President-elect Donald Trump’s recent threats to impose tariffs on companies that move work abroad.